Roman numerals for popular use are:

I=1, V=5, X=10, L=50, C=100, D= 500 and M= 1000

Now you need to know the rules for forming numbers, such as not writing a value more than three times in a row, if a lower value letter is written on the left, subtract from the one on the right, if it goes to its right, add.

Examples:

3 = III

4 = IV

11=XI

59 = LIX

60 = LX

1900 = MCM

1953 = MCMLIII

I don't think it's necessary to talk about how to use a keyboard